Shorter days and longer nights are the norm in the Northeast this time of year.

Instead of begrudging the diminished daylight, use the coming December solstice as an opportunity to help your child learn some science.

The winter solstice is considered the start of winter in the Northern Hemisphere – or at least the astronomical winter, which runs Dec. 21-March 20, 2015. Meteorological winter (the one most of us think about when we see snow on the ground) is defined by the three coldest months of the year and runs Dec. 1-Feb. 28.

The word “solstice” is derived from the Latin word solstitium; sol from “sun” and – stitium, “a stoppage.” As we move from summer to winter, the spot on the horizon where the sun rises and sets moves southward each day. Because the sun’s path across the sky dips each day, the sun’s position at high noon also moves southward as well.

At the winter solstice, the sun’s path reaches its southernmost position, and the sun is at its farthest distance from the northern axis of the earth. The day following the solstice, the path begins to move northward. In the days just before and after the winter solstice, the southern/northern movement of the sun is so slight that is appears to stand still (hence, the stoppage).

The solstice occurs at the same moment everywhere on Earth. Those of us who live in the northeast will experience the 2014 winter solstice on Dec. 21 at 6:03 p.m. The solstice days are those with the fewest hours of sunlight during the whole year in the Northern Hemisphere. This year, there will be approximately 9½ hours of sunlight, 14½ hours of darkness.

Cultural celebrations

There are many cultural celebrations that take place around what is considered the start of the solar year, which is a celebration of light and the rebirth of the Sun.

Other interesting facts:

The solstice can occur anytime from Dec. 20-23, though it most frequently falls on Dec. 21 or Dec. 22.

The solstice is translated from Universal Time. For countries in Europe, Asia and Africa, as well as Australia and New Zealand, the 2014 solstice actually occurs on Dec. 22.

At high noon on the winter solstice, the sun is directly overhead at the latitude called the Topic of Capricorn.

Check your shadow around noontime in the days around the winter solstice. It’s your longest noontime shadow of the year.

There’s a reason for the difference in seasons. While the earth rotates around the sun, it also spins on its axis, which is tipped at an angle (23.5 degrees towards the plane of its rotation). The tilt causes the Northern Hemisphere to receive less direct sunlight (winter) and the Southern Hemisphere to get more direct sunlight (summer). The earth’s continual orbit means that, over time, the hemisphere pointing closest to the sun changes and the seasons are reversed. (View a picture of Earth’s orbit.)

What happens after the winter solstice? The sun begins to appear farther above the horizon. The movement culminates in the longest day of the year on June 21, known in the Northern Hemisphere as the summer solstice.

March 21 and Sept. 21 are known as “equinoxes,” when the Earth’s equator passes the center of the sun. The hours of day and night on these two dates are almost equal.